Coming from Greece in the early 5th century Democritus and Leucippus are the fellows who came up with the first atomic theory. They believed that everything was made up of tiny, invisible and unchangeable particles that they called "atomos" (greek for atoms).

They believed that there were uncountable numbers of atoms but that they could only form a finite number of different combinations. When things die the atoms they contain are dispersed and become part of other combinations.

They left no room for god in their theorizing. Their theory, called atomism, opened the door to additional scientific inquiry.